Circuit interrupting device



Oct. 30, 1956 H. J. LINGAL CIRCUIT INTERRUPTING DEVICE 3 Sheets-Sheet 1Filed Oct. 26. 1951 INVENTOR Hurry J.Lingo|. YQ/

' WITNESSES: 274" Oct. 30, 1956 H. J. LINGAL CIRCUIT INTERRUPTING DEVICE3 Shecs-Sheet 2 Filed Oct.

Arc- Extinguishing 60s Arc-Extinguishing Gas WITNESSES:

INVENTOR HO J.L' I. Y will mg? Get. 30, 1956 H. J. LINGAL 2,769,063

CIRCUIT INTERRUPTING DEVICE Filed on. 26,-1951 s Sheets-Sheet a[(Arc-Exfinguishing Gos M32 n7 Insulation us I 200 Arc-Extinguishing GosWITNESSES: INVENTOR ZWW/ Hurry J.Lingo|.

T W 152 lis Insulohon United States Patent CIRCUIT INTERRUPTING DEVICEHarry J. Lingal, Pittsburgh, Pa., assignor to Westinghouse ElectricCorporation, East Pittsburgh, la., a corporation of PennsylvaniaApplication October 26, 1951, Serial No. 253,321

26 Claims. (Cl. 200-146) This invention relates to circuit interruptingdevices in general, and, more particularly, to disconnecting switcheswith particular relation to disconnecting switches that are adapted tobe opened under load conditions. My application Serial No. 576,875 filedApril 9, 1956, is a division of this application.

In many instances it is desirable to open a high voltage disconnectingswitch while normal load current is flowing in the circuit in which itis connected. For example, in many installations, high voltagetransformers are constantly connected to the high voltage line andinfrequently require servicing. It is then necessary to disconnect sucha high voltage transformer from the high voltage circuit, and duringsuch disconnecting operation it is necessary to interrupt themagnetizing current flowing from the high voltage line into the highvoltage transformer.

If this magnetizing current were drawn between the blade-shaped contactand the stationary jaw contact of a conventional disconnecting switchthe contact surfaces would become pitted or eroded so that followingonly a few such operations the contact surfaces would not be suitablefor carrying the full load current. Thus the switch members would becomeburned or fused because of the heat of the arc depending upon the amountof current in the circuit at the particular instant that the switch isopened.

There is also the possibility, under more severe circuit conditions,that a long arc may be sustained and establish itself between the switchand an adjacent circuit or ground when the attempt is made to interruptthe load current by a conventional disconnecting switch. It is a generalpurpose of my invention to provide an improved load-break disconnectingswitch which will interrupt the load current interiorly within an arcinterrupting structure and not exteriorly thereof at the open switchcontacts.

A further object of my invention is to provide an improved and highlyefficient load-break disconnecting switch in which the contact structureof the arc-extinguishing device is opened and closed by snap action.

Still a further object of my invention is to'provide an improvedoperating mechanism for the arc-interrupting device of a load-breakdisconnecting switch.

Yet another object is to provide a load-break disconnecting switch inwhich the circuit is broken within the arc-interrupting device, and,during the closing operation, the circuit is made between the contactsof the arc-interrupting device and not at the switch contact members.

Still a further object of my invention is to provide a load-breakdisconnecting switch particularly suitable for interrupting high voltagecircuits, in which use is made of the length of the arc-interruptingdevice for holding the voltage during high voltage operation.

A further object is to provide an improved snap-acting toggle mechanismfor the arc-interrupting device of a load-break disconnecting switch.

A further object is to provide an improved load-break 2 disconnectingswitch particularly suitable for enclosing an arcextinguishing gas in asealed state, and to provide improved sealing structure to preventescape of the gas.

Still a further object is to provide improved and highly etlicientload-break disconnec switch which may be economically manufactured,simple to service and which will give a long trouble-free interruptinglife.

Further obi-sets of my invention will readily become apparent uponreading the following specification, taken in conjunction with thedrawings, in which:

Figure l is a plan view of my improved load-break disconnecting switch,the contact structure being illustrated in the closed circuit position;

Fig. 2 is a side elevational View of the load-break disconnecting switchpictured in Fig. l, the contact structure being shown in the closedcircuit position, the figure also showing the fully open circuitposition in chain lines;

Fig. 3 is a vertical sectional view, drawn to an enlarged scale, of thearc-interrupting device of the load-break disconnecting switchillustratedv in Figs. 1 and 2, the contact structure being shown in theclosed circuit position;

Fig. 4 is a sectional plan view taken substantially along the line lV-IVof Fig. 3, the contact structure being shown in the closed circuitposition;

Fig. 5 illustrates a modified type of 1oad-break disconnecting switch,the contact structure being illustrated in the closed circuit position;

Fig. 6 is a view similar to that of Fig. 5, showing the modified type ofload-break disconnecting switch in the open circuit position; and

Fig. 7 is a fragmentary vertical sectional view through a portion of amodified type of load-break disconnecting switch, similar to that setout in Figs. 5 and 6, the contact structure being shown in the closedcircuit position.

Referring to the drawings, and more particularly to Figs. 1 and 2thereof, it will be observed that there are provided three stacks ofinsulator columns 1, 2 and 3 supported upon a suitable base structure it(Fig. l). The insulator stacks 1, 2 and 3 may extend a considerabledistance upwardly from the base structure it? when the switch isutilized on a high voltage circuit. Preferably, the insulator columns 1and 3 are fixed, whereas the insulator column 2 is adapted for rotatingmovement by a crank arm 2a, to effect thereby operation of the mechanismfor the load-break disconnecting switch, generally designated by thereference numeral 4, and which is supported at the upper ends of theinsulator columns l3.

Supported at the top of stationary insulator column 1 is anarc-extinguishing interrupting device, generally designated by thereference numeral 6. Also supported at the top of the stationaryinsulator column 1 is a relatively stationary jaw switch contact,designated by the reference numeral 7, and which cooperates with thecontacting end 8 of a disconnecting switch blade 9, which is secured toa cam housing 11, the latter being pivotally supported by trunnions 12.The trunnions 12 extend inwardly from a housing casting 13, which has anextension including a line terminal plate 15.

The other line terminal plate of the load-break disconnecting switch 4is designated by the reference numeral 16, and constitutes an extensionof a support casting 17 fixedly supported at the top of insulatorcolumn 1. Thus the circuit passes through the disconnecting switch 4from line terminal plate 16, support casting i7, stationary jaw contact7, movable contact 8 of switch blade 9, through the switch blade 9 toconducting cam open circuit position, as indicated by the chain lines 18of Fig. 2. In this position a long isolating gap in air is providedbetween the switch contacts at opposite potential. As shown in Figs. 1and 2, the interrupting device 6 is mounted out of the space between theterminals 13, and 16, 17 so that the isolating gap between them is notreduced, and the flashover voltage between live parts is maintained thesame as in an ordinary disconnecting switch having the same insulatorspacing.

Referring more particularly to Fig. 3, which more clearly showstheinternal construction of the arc-extinguishing interrupting device 6,it will be observed that this device includes a weatherproof porcelaincasing 19, supported vertically upon the support casting 17. Theengagement between the lower end of the porcelain casing 19 and thesupport casting 17 may be eflected by a suitable cement 29, interposedbetween a lower corrugated portion 21 of the ceramic casing 19 andinteriorly disposed corrugations 22 provided within an upstanding flangeportion 23, the latter being secured by suitable means, not shown, tothe casting 17.

At the upper end 24 of the weatherproof casing 19 is fixedly secured bycement 25 a mounting flange 26, the latter being secured by bolts 27 toa mechanism housing casting 28, the latter having a cover plate 29.Preferably, the cover plate 29 is secured by bolts 30 to the housing 28,a suitable gasket 31 being interposed thercbetween to etfect a gas-tightconnection.

Disposed interiorly within the weatherproof casing 19 is anarc-extinguishing unit, generally designated by the reference character32, and including an upstanding insulating cylinder 33 within whichreciprocates a movable contact rod 34 having a piston 35 secured theretoand making a relatively close lit with the interior wall of theinsulating cylinder 33.

A movable contact 36, secured to the lower end of the movable contactrod 34-, makes abutting engagement with a relatively stationary contact37, the latter being resiliently supported by means of a contactcompression spring 38. The contact compression spring 38 is disposedwithin a stationary contact support tube 39, which has a stationary pin49 extending therethrough near its upper end. The pin 49 extends throughan elongated slot 41 provided near the lower end of the stationarycontact 37, so that during the closing stroke the stationary contact 37may move resiliently downwardly with respect to the support tube 39 andthe pin 40, compressing the spring 38 for the requisite contact pressurebetween the stationary and movable contacts 37, 36, respectively. Aflexible conducting strap 39a electrically interconnects the stationarycontact 37 with a conducting base 42, hereinafter described.

I mount the support tube 39 upon a conducting base 42, which is secured.as by threaded engagement, to a conducting closure plate 43, the latterbeing secured by means not shown to the flange portion 23 of the supportcasting l7. Disposed at the lower end of the conducting base 42 is apressure gauge 44, which may be visually observed from below the basestructure 10 for the loadbreak disconnecting switch 4. Thus a stationattendant may look upwardly from the base structure 10 for theload-break disconnecting switch 4, and observe the pressure registeredupon the dial of the pressure gauge 44. This pressure gauge 44 indicatesthe gas pressure which is present within the interior 45 of the casing19, the latter, as previously mentioned, having a gas-tightconstruction.

'I prefer to fill the casing 19, by way of the gauge ati effect collapseof the toggle link 7 and toggle link 61 4 1951, Serial No. 237,502, byHarry J. Lingal, Thomas E. Browne, Jr., and Albert P. Strom and assignedto the assignee of the instant application, and issued on July 31, 1951,as Patent No. 2,757,261.

The movable contact rod 34 is moved upwardly within the insulatingcylinder 33 by a snap-acting over-center toggle mechanism, generallydesignated by the reference numeral 46, and enclosed interiorly withinthe mechanism housing casting 28. This mechanism 46 includes a U-shapedbracket 47 secured by a pair of bolts 48 to a support portion 49 of thecasting 28. The U-shaped bracket 47 has apertures provided in itsupstanding legs 54 through which extends a pivot pin 51. Supported onthe pivot pin 51 is a U-shaped link 52, the legs 53 of which haveapertures provided at their upper ends. A pivot pin 54 extends throughthe apertures provided in the upper ends of the legs 53, and supports aU-shaped arm 55, the configuration of which is more clearly shown inFig. 4. One leg 56 of the arm 55 is longer than the other leg 57, and ispivotally connected at its outer extremity, as at 58, to the upper endof the movable contact rod 34.

At the extremity of the other leg 57 of the arm 55 is an aperture,through which passes a pivot pin 59, the latter also extending throughan aperture 60 provided intermediate the ends of the longer leg 56 ofthe arm 55.

The pin 59 supports a U-shaped toggle link 61 at the left-hand endthereof, as viewed in Fig. 3. The righthand ends of the legs 62, 63 ofthe toggle link 61 are slotted, as at 64. The slot 64 of the upper leg62 of the toggle link 61, as viewed in Fig. 4, is mounted upon atrunnion 65, the latter being journalled in a bearing portion 66provided in the side wall 67 of the housing casting 28.

The slot 6- of the lower leg 63 of the toggle link 61, as viewed in Fig.4, accommodates a crankshaft 68, more clearly shown in Fig. 4. Thetrunnion 65 also supports one leg 69 of a toggle link, generallydesignated by the reference numeral 7-1), the lower "leg 71 of which hasa collar 72 secured thereto, as by brazing, which is fixedly secured tothe inner end of the crankshaft 63 by a key pin 73, as shown in Fig. 4.

Thus, rotation of the crankshaft 68 will effect rotation of toggle linksecured thereto, effecting thereby opening and closing of the contactstructure associated with the arc-extinguishing unit 32.

Preferably a tension spring 75 is interposed between the pin 59 and apin 76 extending through apertures 77 provided in the legs 69, 71 of thetoggle link 7d. Spacers 73 are employed encircling the pins 59, 76, tomaintain the tension spring 75 at a relatively fixed location. A stop $9is provided, constituting an upwardly projecting boss of the casting 28,which arrests clockwise rotation of the toggle link 7% as shown in Fig.3. A second stop 81, which is preferably made adjustable, is providedextending downwardly from the cover plate 29 to strike the toggle link61 during the opening operation, to arrest the same, as shown by thechain lines 32 in Fig. 3. An adjustable stop 70:! is provided to arrestOOdIlllfiIClOCl-iWiSQ rotation of toggle link 71 during the openingoperation. The tension spring '75, as more clearly shown in Fig. 3, to

ill the open and closed circuit positions of the interrupter, asindicated in Fig. 3. 7

It will be noted that the crankshaft 63 extends through a bearingportion 83 provided in the side wall of the casting 28, and also extendsthrough a laterally jutting gas-tight housing 85, more clearly shown inFig. 4. The gas-tight housingSS comprises, as shown, a cylindricalportion which may be welded, as at 86, to the side wall 85 of thecasting 28. The housing 85 also includes an aper- As more clearly shownin Figs. 1-, 2 and 4', the operating cran includes a plate 89 having aportion 90 removed therefrom to make it of lighter construction. Alsothe plate 89 has two triggers or engaging shafts 91, 92, as more clearlyshown in Fig. 2, which are engaged during the opening and closingoperations by the contact end 8 of the disconnecting switch blade 9.

Consequently, during the opening operation of the loadbreakdisconnecting switch 4, the contact end 8 of the switch blade 9 engagesthe engaging shaft 91 of operating crank 88 to ebfect thereby rotationof crankshaft 68 to eflect an extension of the tension spring 75 whenthe toggle link "it? is moved counterclockwise, as viewed in Fig. 3.When the pins 59, 76 and crankshaft 68 are on a straight line themechanism 46 is in its fully extended condition. Furthercounterclockwise rotation of crankshaft 68 will efiect collapse of thetoggle link 70 and toggle link 61, as indicated by the chain lines 82 ofFig. 3. The result will be a snap-opening motion of the movable contact35 upwardly away from the relatively stationary contact 37 and acompressing of the gas Within the region 93 on the upper side of thepiston 35. The piston 35 will consequently compress the gas within theregion 93 and compel it to flow through the nozzle 94 of an orificemeber 93, through which the load current arc is drawn. The flow of thecompressed gas through the orifice member 95' will effect extinction ofthe are drawn between contacts 36, 37, the hot gases passing out one ormore vents 79 through the base 42.

After operating crank 88 has been snapped to its upper position, asviewed by the chain lines 96 of Fig. 2, the

location of the engaging shaft 91 in this position is clear of the lineof movement of switch blade 9; and switch blade 9 continues to move tothe fully open circuit position of the switch, as indicated by the chainlines 18 of Fig. 2.

During the closing operation the contact end 8 of switch blade 9, inmoving in a counterclockwise direction about pivots 12, as viewed inFig. 2, will strike engaging shaft 92, which at this time is in the lineof movement of switch blade 9.

The switch blade 9 will hence strike engaging shaft 92 to fcrceablyeffect clockwise rotation'of operating crank and hence also ofcrankshaft 68, to thereby effect clockwise rotation of toggle link 70from its chain line position 9'7, as viewed in Fig. 3, to its full lineposition as viewed in Fig. 3. As in the opening operation, so in theclosing operation the tension spring 75 is first extended and theneffects collapse of the toggle link 61 and the toggle link so to effecta snap-closing motion of the contacts 36, 37.

To enable the e.ectrical circuit to pass through the arcextinguishinginterrupting device 6 following separation of the contact end 8 of theswitch blade 9 from the stationary jnv contact 7, i provide an auxiliaryconducting contact arm 99 pivotaily mounted about a pivot 100, which isin registry with the pivot axis 12. As more clearly shown in Fig. 2, thefree end 101 of the auxiliary contact arm 99 contacting enga ement witha stationary U- shaped contact or terminal 102 fixedly secured by boltsto the cover plate 29 of the housing 28. Means are provided to bias theauxiliary contact arm 99 toward the switch blade 9, in this instanceincluding a spring tube 104 within which a compression spring 107. Thecompression spring it? is seated at its lower end, as viewed in Fig. 2,against a cap it of the spring tube 104. Th upper end of the compressionspring 1%7 is seated against apertured s )ri plate i071; secured to thefree end of a spring rod 143. The lower end of the spring rod 105 ispivotal y mounted at a movable pivot 106 of the cam housing Iii, moreclearly shown in Fig. l of the drawings. Fundamentally, the spring tube194 acts somewhat as a tension spring tobias the two arms 9, 99together. Also the switch blade 9 has a laterally extending book 5 whichengages the arm 99 during the opening operation to carry the lattertherewith to the fully open position.

From the foregoing description, it will be readily apparent how theload-break disconnecting switch 4 operates. However, to recapitulate, inthe closed circuit position of the device the electriral circuitthercthrough includes line terminal plate 16, support casting i7,stationary jaw contact 7, movable contact 8 of switch blade 9, throughthe switch blade 9 to conducting cam housing 11, and thence throught-runnions 12 and casting 13 to line terminal plate 15.

A separate circuit in parallel to that mentioned is available in theclosed circuit position or" the device. It includes line terminal plate16, support casting 17, conducting flange portion 23, plate 43,conducting base i2, flexible conductor 39a, stationary contact 37,movable contact 36, movable contact rod 34, flexible condoctor 74 to themechanism housing 28, through terminal 102 and auxiliary contact arm 99to cam housing 11, and thence through trunnions 12 and casting 13 toline terminal plate 15. Since the second parallel circuit through theinterrupting device 6 contains more resistance than the main circuitdirectly through the switch blade 9, practically all the current flowsthrough the first-mentioned circuit including switch blade 9.

To open the switch 4 from the closed circuit position thereof suitablemeans, not shown, etiects counterclockwise rotation of the crank arm 2::and hence insulator column 2, as viewed in Fig. 1. This rotatingmovement of insulator column 2 actuatcs a cam interiorly within camhousing 11 in a manner more fully disclosed in United States Patent2,436,296, issued February 17, 194-8, to Howard W. Graybill and PaulOlsson assigned to the assignee of the instant application. The firstportion of the cam motion effects a twisting, or axial rotation of theswitch blade 9 so that any ice formed between the stationary and movablecontacts 7, 3 may be broken free.

Following such initial twisting motion of the switch blade 9, the cammotion taking place within the cam housing 11, as set out in theaforesaid patent, causes clockwise rotative movement of the switch blade9 about the pivot 12, as viewed in Fig. 2. When the contacting portion 3of switch blade 9 separates from stationary jaw contact 7 the electricalcircuit is then forced to take the second parallel path previouslymentioned through the arc-extinguishing interrupting device 6. Thiscircuit includes line terminal plate 16, support casting 17', conductingflange portion 23, plate 43, conducting base 42, flexible conductor 39a,stationary contact 37, movable contact 36, movable contact rod 34-,flexible conductor 74 to the mechanism housing 28, through terminal 102and auxiliary contact arm 99 to cam housing 3.1, and thence throughtrunnions 12 and casting 13 to line terminal plate 15.

Continued clockwise rotation of switch blade 9 brings the free end 3thereof into engagement with engaging shaft 91 to eifect therebycounterclockwise rotative motion of operating crank 83 and hence openingmotion of the mechanism 46, as previously described. This will etfectopening of the contact structure 36, 3'7 and extinction of the are drawntherebetween through the orifice member by a flow of gas, which iscompressed above the piston 35 within the region 93.

When this arc is extinguished, the electrical circuit through theload-break disconnecting switch 4 is interrupted. Continued clockwisemovement of switch blade 9 causes hook 5 to strike arm 99 and brings theblade 9 and arm 99 to the open circuit position, as shown by the chainlines 13 of Fig. 2. It is to be noted that the spring tube 104, beingequivalent to a tension spring, maintains the auxiliary contact arm 99in contact with contact 102 until struck by hook 5 of blade 9.

To eifect a closing of the switch 4, it is merely necessary to cause, bya suitable mechanism, clockwise rotative movement of crank arm 2a andhence the insulator column 2, as viewed in Fig. 1. This will causethrough the cam motion taking place within the cam housing 11, firstcounterclockwise rotative movement of the switch blade 9, as viewed inFig. 2, the auxiliary contact arm 99 being moved therewith byfunctioning of the spring tube 104 and gravity.

Near the end of the closing stroke the contact arm 99 strikes thestationary contact 102. Further movement causes a separation to occurbetween the switch blade 9 and the contact arm 99, with the contact end8 of switch blade 9 striking engaging shaft 92 of operating crank 88,which at this time is in the path of movement of switch blade 3. Thecontact 8 will strike engaging shaft 92 and will effect therebyclockwise rotation of operating crank 88 to effect closing movement ofthe mechanism 46 disposed interiorly within mechanism housing'casting28; This will effect snap-action closing engagement between the contacts36, 37 to bring about closing of the electrical circuit through theload-break disconnecting switch 4 prior to the closing of the contacts7, 8.

Finally, the contact 8 of switch blade 9 engages jaw contact 7, and thefinal movement of the cam mechanism within cam housing 11 is to effectan axial twisting motion of switch blade 5 to bring about firmcontacting engagement between contacts 7, 8. This final closing movementbetween contacts 7, 8 will effectively short out the shunting circuitextending around contacts 7, 8 by way of contact arm 99 and contacts 36,37 disposed interiorly within arc-extinguislnng interrupting device 6.Because of the lower resistance be tween contacts 7, 8 practically allof the load current carried by the switch 4 will pass between thecontacts 7, 8, and not through the shunting circuit extending throughthe interrupting device 6 and the auxiliary contact arm 99.

As mentioned previously, I desire to make the arcextinguishinginterrupting device 6 gas-tight toprevent any leakage of the gas, suchas sulfur hexafiuoride, existing under some pressure, say one or twoatmospheres absolute, within the casing 19. However, to effect actuationof thet mechanism 46 from a point exteriorly of the extinguishing device6, it is necessary to prevent leakage of gas along the crankshaft 68. Animportant feature of my invention is the means for preventing suchleakage of gas along the crankshaft 63, and this includes a sleeve 108of rubber, or synthetic rubber, clamped to the crankshaft 68 at thepoint 109 by a U-shaped clamp 110, the legs of which may be forcedtogether by a bolt 111. To prevent any frictional forces coming intoplay, preferably the external surface of the crankshaft 68, beneath thesleeve 163, is coated with a dry lubricant, such as graphite. Also thelower end of the sleeve 163, as viewed in Fig. 4, is secured by a clamp112 to a flange portion 113 forming an integral part of closure plate37. Another clamping bolt 111 may be employed to secure the two legs ofthe U-shaped clamp 112 into firm engagement. 7

With this construction, it will be observed that should there occur anyleakage of sulfur hexafluoride gas along the crankshaft 68 past thebearing portion 83, this gas will merely collect in the region 114within housing 85', and will not be able to escape either past theflange por- 7 tion 113'or axially along the crankshaft 68; Moreover,

any pressure existing within the region 114 will not tend to deform thesleeve 108 of resilient material inasmuch as-any compression of thelatter will be resisted by the crankshaft 68 itself. I i

Thus there has been disclosed a gas-tight or liquidtight seal 168, whichwill permit rotation of the shaft 68 through. an arc of about 120",which is the maximum usally required in circuit interrupter mechanisms.It brings about a tight seal and yet offers little resistance to shaftrotation. Further, relatively large pressures can 8 be held withoutleakage, loss or harm to the seal because movement of the elastic tubewalls is limited by the shaft which it surrounds and seals.

Referring to Figs. 5 and 6 of the drawings, it will be observed that Ishow a modified type of load-break disconnecting switch, generallydesignated by the reference character 115, including a pair ofstationary columns 116, 117 mounted upon a suitable base 118. The upperend of insulator column 116 supports a hinge contact 119 and adisconnecting switch blade 121i, pivotally mounted, as at 119a, to thehinge contact 119. A line terminal 121 is formed by an extension ofhinge contact 119. 1

Suitable means, such as a manually operated hook-stick engaging ahook-eye 126a, may be provided to cause engagement of the freecontacting end 122 of switch blade 121) with a jaw contact 123, thelatter being supported at the upper end of insulator column 117.

Associated with the jaw contact 123 is a pivotally mounted rotatablearc-extinguishing device, generally designated by the reference numeral124, and including a plurality of conducting metal balls 125 disposedinteriorly within an insulating tube 126, such as fiber. The insulatingtube 126 is, in turn, surrounded by a weatherproof casing 127 formed ofa suitable ceramic weatherproof material, such as porcelain. A closurecap 128 is provided at the right-hand end of the extin uishing device124, and the cap 128 has a tongue extension 129, which is pivotallysupported at 130 on a hinge contact 131. The hinge contact 131 ismounted upon a horizontally extending conducting plate 132, which is, inturn, supported at the upper end of the insulator column 117.

At the left-hand end of the extinguishing device 124 is a second closurecap, generally designated by the reference numeral 133, and havingintegrally formed actuating portions 134, 135.

In the closed circuit position of the load-break disconnecting device115, as viewed in Fig. 5, the electrical circuit therethrough includesline terminal 121, hinge contact 119, disconnecting switch blade 121),jaw contact 123 and conducting plate 132 to the second line terminal136, which preferably constitutes an extension of the conducting plate132. v

To effect opening of the load-break disconnecting switch suitable means,not shown, effects counterclockwise rotative motion of switch blade 120,as viewed in Fig. 5. This causes contacting engagement between the freeend 122 of switch blade 121) and the actuating portion 134 of closurecap 133. Such engagement between free end 122 of switch blade andactuating portion 134 causes clockwise rotative movement ofarcextinguishing device 124 about the pivot 13%. Meanwhile theconducting balls maintain contact between the closure caps 128, 133.Finally, the contact end 122 of switch blade 120 separates from jawcontact 123 so that the circuit now extends through the extinguishingdevice 124 by way of the conducting actuating portion 134, closure cap133, conducting balls 125 to line terminal 136 by way of hinge contact131.

Further upward swinging movement of switch blade 120 effects rollingmotion of all the balls 125 toward the pivoted end of the extinguishingdevice 124, as shown more clearly in Fig. 6. The circuit is,consequently, broken within the region 137 interiorly within insulatingtube 126, which preferably contains a suitable arc-extinguishing gas,such as sulfur hexafiuoride. Further opening movement of switch blade12%) brings the latter to the open circuit position, as shown in Fig. 6.

To effect closing of the disconnecting switch 115, the switch blade 120is rotated in a clockwise direction, as viewed in Figs. 5 and 6. Itfinally makes contact with the actuating portion 135, and, in strikingthe extinguishing device 124, the balls 125 are thrown into a bridgingrelationship between closure caps 123, 133 so that the circuit is madeduring the closing operation within the extinguishing device 124, andnot at the stationary jaw contact 123.

Further movement effects contact engagement between the free end 122 ofswitch blade 120 and jaw contact 123 to thereby short out theextinguishing device 124 because of the lower resistance between thecontacts 122, 123.

in certain instances, it may be desirable to effect contact closurebetween the contacts 122, 123 and not through the extinguishing device124. In such an event a moditied extinguishing device, generallydesignated by the reference numeral 133, is provided, as pictured inFig. 7. in the modified extinguishing device 138, the actuating portion135a is formed of insulating material, so that during the closing strokethe stroking of the contacting end 122 of switch blade 129 withactuating portion 135a will not complete the circuit through theextinguishing device 138. The circuit will only be closed by actualengagement between contacts 122, 123. Otherwise the extinguishing device138 is identical with the extinguishing device 124, previouslydescribed; consequently a further description of the operation thereofappears unnecessary.

From the foregoing, it will be apparent that 1 have provided an improvedload-break disconnecting switch in which the electrical circuit isinterrupted through an auxiliary arc-extinguishing interrupting deviceand not at the disconnecting switch blade contacts. Thus the switchblade contacts are maintained free from pitting and erosion and arecapable of good contacting engagement in the closed circuit position ofthe device, in which position the extinguishing unit is shorted out ofthe circuit. The devices are simple and economical to make and will givelong operational life.

Although a certain gas has been suggested for use in the extinguishingdevice 32 of Figs. 1-4 and the extinguishing devices 124, 138 of Figs.5-7, nevertheless other extinguishing gases may well be employed. I havemoreover shown an arrangement for providing a gas-tight seal preventingescape of the gas lengthwise of an operating shaft, and i have shown howthe mechanism and the contact structure may be opened and closed with asnap action preferably employing a suitable piston for facilitatingextinction of the are by means of a blast of compressed gas.

Although i have shown and described specific structures, it is to beclearly understood that the same were merely for the purpose ofillustration, and that changes and modifications may readily be madetherein by those skilled in the art, without departing rom the spiritand scope of the appended claims.

I claim as my invention:

1. A load-break switch including a pair of spaced terminals, arelatively stationary switch contact on one of said terminals, adisconnecting switch blade bridging the switch terminals in the closedcircuit position and adapted to be moved into and out of swingingengagement with the relatively stationary switch contact, anarc-extinguish ing interrupting device having one end thereof disposedadjacent said relatively stationary switch contact and having the otherend thereof extending away from said relatively stationary switchcontact, contact structure for said arc-extinguishing interruptingdevice including a pair of separable contacts, a mechanism for actuatingthe contact structure, a relativeiy stationary terminal carried on saidother end of the arc-extinguishing interrupting device, meanselectrically connecting one of the separable contacts or" theinterrupting device to said relatively stationary switch contact, meanselectrically connecting the other separable contact of the interruptingdevice to the relatively stationary terminal thereon, means for causingthe opening movement of the switch blade to operate said mechanism, andan independent auxiliary contact arm remaining relatively stationaryduring the initial movement of the switch blade and subsequently movableat least during a portion of the opening operation with the switch bladeand electrically interconnecting the relatively stationary terminal ofthe interrupting device with the other terminal of the switch spacedtherefrom.

2. A load-break switch including a pair of spaced terminals, arelatively stationary switch contact on one of said terminals, 21disconnecting switch blade bridging the switch terminals in the closedcircuit position and adapted to be moved into and out of swingingengagement with the relatively stationary switch contact, said switchblade being mounted for rotary movement about an axis extending alongthe length of the blade for making and releasing pressure engagementwith said relatively stationary switch contact, means for causing saidrotary movement of the switch blade at the end of its swinging movementinto closed circuit position to make said pressure engagement and at thebeginning of its swinging movement away from closed circuit position torelease said pressure engagement, an arc-extinguishing interruptingdevice having one end thereof disposed adjacent said relativelystationary switch contact and having the other end thereof extendingaway from said relatively stationary switch contact, contact structurefor said arc-extinguishing interrupting device including a pair ofseparable contacts, a mechanism for actuating the contact structure, arelatively stationary terminal carried on said other end of thearc-extinguishing interrupting device, means electrically connecting oneof the separable contacts of the interrupting device to said relativelystationary switch contact, means electrically connecting the otherseparable contact of the interrupting device to the relativelystationary terminal thereon, means for causing the opening movement ofthe switch blade to operate said mechanism, and an auxiliary contact armremaining in engagement with said relatively stationary terminal on theinterrupting device during the rotary movement of the switch blade andduring the initial swinging movement of the switch blade until afterseparation of the contacts in the interrupting device and said auxiliarycontact arm being subsequently movable at least during a later portionof the opening operation with the switch blade to disengage therelatively stationary terminal on the interrupting device, and saidauxiliary contact arm electrically interconnecting the relativelystationary terminal of the interrupting device with the other terminalof the switch spaced therefrom to provide an auxiliary current paththrough the switch during both said rotary and initial swingingmovements of the switch blade and being spaced from the relativelystationary terminal of the interrupting device when the switch is inopen circuit position.

3. A loadbreak switch including a pair of spaced terminals, a switchcontact on one of said terminals, disconnecting switch blade meansbridging the switch terminals in the closed circuit position of theswitch, means for moving said switch blade means into and out ofswinging engagement with said switch contact, an arc-extinguishinginterrupting device mounted on the terminal having said switch contactthereon and out of the space between the spaced terminals, saidinterrupting device having a tubular insulating member supported at oneend on the terminal having the switch contact thereon, a mechanismhousing supported entirely by the other end of said tubular insulatingmember, both said tubular insulating member and said mechanism housingbeing stationary relative to the terminal on which the interruptingdevice is mounted, an operating arm outside said mechanism housing andhaving a shaft extending pivotally into the mechanism housing, saidoperating arm being pivotaliy movable in opposite directions about theaxis of said shaft during opening and closing movement of the switchblade means, a pair of interrupting contacts one of which is movablewithin said tubular insulating member, a spring mechanism in saidmechanism housing and connected to said shaft and'operated by pivotalmovement of said operating arm, said spring mechanism in the housingbeing connected to said movable interrupting contact, auxiliary contactmeans operable by said switch blade means and completing an electricalconnection with said mechanism housing and the movable interruptingcontact independently of said operating arm and the spring mechanism inthe housing when the switch is closed, the spring of said mechanismholding the movable interrupting contact in engagement with the otherinterrupting contact when said operating arm and said switch blade meansare in closed position and also during the first part of the movement ofthe switch blade means and operating arm in opening direction, saidspring mechanism in the housing acting during further pivotal movementof the operating arm in opening direction to actuate the movableinterrupting contact to disengage the other interrupting contact with asnap action at a speed independent of the speed of movement of theoperating arm and switch blade means, said spring holding saidinterrupting contacts in separated position when the operating arm andswitch blade means are in open position and moving said interruptingcontacts to engaged position with a snap action upon pivotal movement ofthe operating arm in closing direction during closing movement of theswitch blade means.

4. A load-break switch including a pair of spaced relatively stationaryswitch contacts, a disconnecting switch blade bridging the switchcontacts in the closed circuit position and adapted to be moved into andout of swinging engagement with one of the relatively stationary switchcontacts, an arc-extinguishing interrupting device having one endthereof disposed adjacent said one relatively stationary switch contactand having the other end thereof extending away from said one relativelystationary switch Contact, contact structure for said arc-extinguishinginterrupting device including a pair of separable contacts, a mechanismfor actuating the contact structure including a rotatable shaft, saidmechanism including a snap-opening and a snap-closing device to'etlectsnap action of the contact structure, a relatively stationary terminaldisposed adjacent said other end of the arc-extinguishing interruptingdevice, means electrically connecting one of the separable contacts ofthe interrupting device to said one relatively stationary switchcontact, means electrically connecting the other separable contact ofthe interrupting device to the relatively stationary terminal, means forcausing the opening and closing movements of the switch blade to effectrotation of the shaft and hence actuation of the mechanism, an auxiliarycontact arm independent from the switch blade and movable at leastduring a porticn of the opening operation with the switch blade, saidauxiliary independent contact arm remaining substantially stationaryduring the initial portion of the switch opening operation andelectrically interconnecting the relatively stationary terminal with theother relativelystationary switch contact following separation of theswitch blade from said one relatively stationary switch contact.

5. A load-break switch including a pair of spaced relatively stationaryswitch contacts, a disconnecting switch blade bridging the switchcontacts in the closed circuit position and adapted to be moved into andout of swinging engagement with one of the relatively stationary switchcontacts, an arc-extinguishing interrupting device having one endthereof disposed adjacent said one relaively stationary switch contactand having the other end thereof extending away from said one relativelystationary :11 contact, contact structure for said arc-extinguishinginterrupting device including a pair of separable contacts, a mechanismfor actuating the contact structure, a relatively stationary terminaldisposed adjacent said other end of the arc-extinguishing interruptingdevice, means electrically connecting one of the separable contacts ofthe interrupting device to said one relatively stationary switchcontact, means electrically connecting the other separable contact ofthe interrupting device to the relatively stationary terminal, means forcausing the opening movement of the switch blade to operate saidmechanism, a movable independent conducting auxiliary bridging contactarm, said movable independent conducting auxiliary bridging contact armremaining relatively stationary during separation of the switch bladefrom one relatively stationary switch contact and electricallyinterconnecting the relatively stationary terminal with the otherrelatively stationary switch contact, and the switch blade picking upthe independent auxiliary contact arm subsequently in the switch openingoperation to cause it to move therewith.

6. A load-break switch including a pair of spaced relatively stationaryswitch contacts, a disconnecting switch blade bridging the switchcontacts in the closed circuit position and pivotally mounted on oneswitch contact, said switch blade being arranged to be swung about saidone switch contact into and out of engagement with the other relativelystationary switch contact, an arc-extinguishing interrupting devicehaving one end thereof disposed adjacent said other relativelystationary switch contact and having the other end thereof extendingaway from said other relatively stationary switch contact, contactstructure for said arc-extinguishing interrupting device including apair of separable contacts, a mechanism for actuating the contactstructure, a relatively stationary terminal disposed adjacent said otherend of the arc-extinguishing interrupting device, means electricallyconnecting one of the separable contacts of the interrupting device tosaid other relatively stationary switch contact, means electricallyconnecting the other separable contact of the interrupting device to therelatively stationary terminal, means for causing the opening movementof the switch blade to operate said mechanism, and an auxiliary movablecontact arm independent from the switch blade and pivotally mountedadjacent said one switch contact and electrically interconnecting therelatively stationary terminal with said one relatively stationaryswitch contact following disengagement of the switch blade from theother relatively stationary switch contact.

7. A load-break switch including a pair of spaced relatively stationaryswitch contacts, a disconnecting switch blade bridging the switchcontacts in the closed circuit position and pivotally mounted on oneswitch contact, said switch blade being arranged to be swung about saidone switch contact into and out of engagement with the other relativelystationary switch contact, an arc-extinguishing interrupting devicehaving one end thereof disposed adjacent said other relativelystationary switch contact and having the other end thereof extendingaway from said other relatively stationary switch contact, contactstructure for said arc-extinguishing interrupting device including apair of separable contacts, a mechanism for actuating the contactstructure, a relatively stationary terminal disposed adjacent said otherend of the arc-extinguishing interrupting device, means electricallyconnecting one of the separable contacts of the interrupting device tosaid other relatively stationary switch contact, means electricallyconnecting the other separable contact of the interrupting device to therelatively stationary terminal, means for causing the opening movementof the switch blade to operate said mechanism, an auxiliary movableindependent contact arm pivotally mounted adjacent said one switchcontact and movable at least during a portion of the opening operationwith the switch blade, said auxiliary movable independent contact armelectrically interconnecting the relatively stationary terminal withsaid one relativeiy stationary switch contact, and remaining relativelystationary while the switch blade separates from said other relativelystationary switch contact during the opening operation.

8. A load-break switch including a pair of spaced relatively stationaryswitch contacts, a disconnecting switch blade bridging the switchcontacts in the closed circuit position and adapted to be moved into andout of swinging engagement with one of the relatively stationary switchcontacts, an arc-extinguishing interrupting device having one endthereof disposed adjacent said one relatively stationary switch contact;and having the other end thereof extending away from said one relativelystationary switch contact, contact structure for said arc-extinguishinginterrupting device including a pair of separable contacts, a mechanismfor actuating the contact structure, a relatively stationary terminaldisposed adjacent said other end of the arc-extinguishing interruptingdevice, means electrically connecting one of the separable contacts ofthe interrupting device to said one relatively stationary switchcontact, means electrically connecting the other separable contact ofthe interrupting device to the relatively stationary terminal, means forcausing the opening movement of the switch blade to operate saidmechanism, an auxiliary independent contact arm movable at least duringa portion of the opening operation with the switch blade andelectrically interconnecting the relatively stationary terminal with theother relatively stationary switch contact, means biasing theindependent auxiliary contact arm toward the disconnecting switch blade,and the independent auxiliary contact arm remaining relativelystationary during the initial portion of the switch opening operationwhile the switch blade separates from said one relatively stationaryswitch contact.

9. A load-break switch including a pair of spaced relatively stationaryswitch contacts, a disconnecting switch blade bridging the switchcontacts in the closed circuit position and adapted to be moved into andout of swinging engagement with one of the relatively stationary switchcontacts, an arc-extinguishing interrupting device having one endthereof disposed adjacent said one relatively stationary switch contactand having the other end thereof extending away from said one relativelystationary switch contact, contact structure for saidv arc-extinguishinginterrupting device including a pair of separable contacts, a mechanismfor actuating the contact structure including a rotatable shaft, saidmechanism including a snap-opening and a snap-closing device to effectsnap action of the contact structure, a relatively stationary terminaldisposed adjacent saidother end of the arc-extinguishing interruptingdevice, means electrically connecting one 'of the separable contacts ofthe interrupting device to said one relatively stationary switchcontact, means electrically connecting the other separable contact ofthe interrupting device to the relatively stationary terminal, means forcausing the opening and closing movements of the switch blade to eflectrotationof the shaft and hence actuation of the mechanism, an auxiliarycontact arm independent from the switch blade movable at least during aportion of the opening operation with the switch blade and electricallyinterconnecting the relatively stationary terminal with the otherrelatively stationary switch contact, and means biasing the auxiliarycontact arm toward the disconnecting switch blade.

lO. A load-break switch including a pair of spaced relatively stationaryswitch contacts, a disconnecting switch blade bridging the switchcontacts in the closed circuit position and adapted to be moved into andout of swinging engagement with one of the relatively stationary switchcontacts, an arc-extinguishing interrupting device having one endthereof disposed adjacent said one relatively stationary switch contactand having the other end thereof extending away from said one relativelystationary switch contact, contact structure for said arcextinguishinginterrupting device including a pair of separable contacts, a mechanismfor actuating the contact structure, a relatively stationary terminaldisposed adjacent said other end of the arc-extinguishing interruptingdevice, means electrically connecting one of the seperable contacts ofthe interrupting device to said one relatively stationary switchcontact, means electrically connecting the other separable contact ofthe interrupting device to the relatively stationary terminal, means forcausing the opening movement of the switch blade to operate saidmechanism, a movable conducting auxiliary contact arm independent fromthe switch blade and electrically inter- 14 connecting the relativelystationary terminal with the other relatively stationary switch contact,said contact arm being pivotally mounted adjacent said other relativelystationary switch contact, and means biasing the auxiliary contact armtoward the disconnecting switch blade.

ll. A load-break switch including a pair of spaced relatively stationaryswitch contacts, a disconnecting switch blade bridging the switchcontacts in the closed circuit position and pivotally mounted on oneswitch contact, said switch blade being arranged to be swung about saidone switch contact into and out of engagement with the other relativelystationary switch contact, an arc-extinguishing interrupting devicehaving one end thereof disposed adjacent said other relativelystationary switch contact and having the other end thereof extendingaway from said other relatively stationary switch contact, contactstructure for said arc-extinguishing interrupting device including apair of separable contacts, a mechanism for actuating the contactstructure, a relatively stationary terminal disposed adjacent said otherend of the arcextinguishing interrupting device, means electricallyconnecting one of the separable contacts of the interrupting device tosaid other relatively stationary switch contact, means electricallyconnecting the other separable contact of the interrupting device to therelatively stationary terminal, means for causing the opening movementof the switch blade to operate said mechanism, an auxiliary movablecontact arm independent from the switch blade pivotally mounted adjacentsaid one switch contact and electrically interconnecting the relativelystationary terminal with said one relatively stationary switch contact,and means biasing the auxiliary contact arm toward the disconnectingswitch blade.

12. A load-break switch including a pair of spaced relatively stationaryswitch contacts, a disconnecting switch blade bridging the switchcontacts in the closed circuit position and adapted to be moved into andout of swinging engagement with one of the relatively stationary switchcontacts, an arc-extinguishing interrupting device having one endthereof disposed adjacent and mounted on said one relatively stationaryswitch contact and having the other end thereof extending away from saidone relatively stationary switch contact, contact structure for saidarc-extinguishing interrupting device including a pair of separablecontacts one of which is carried on a rod of conducting material movablelongitudinally of the interrupting device, mechanism for actuating thecontact structure including a pivoted linkage in the interrupting deviceand a rotatable shaft extending externally of the interrupting deviceand having an operating crank secured to the external end thereof, saidcrank having two spaced shafts at the end thereof by which the crank maybe engaged one of which shafts is in the line of motion of the end ofthe switch blade on opening and the other of which is in the line ofmotion of the end of the switch blade on closing, and said two spacedshafts with the end of the rotatable shaft forming a triangulararrangement.

13. A load-break switch including a pair of spaced relatively stationaryswitch contacts, a disconnecting switch blade bridging the switchcontacts in the closed cir zit position and adapted to be moved into andout of swinging engagement with one of the relatively stationary switchcontacts, an arc-extinguishing interrupting device having one endthereof disposed adjacent said one relatively stationary switch contactand having the other end thereof extending away from said one relativelystationary switch contact, contact structure for said arc-extinguishinginterrupting device including a pair of separable contacts, a relativelystationary terminal disposed adjacent said other end of thearc-extinguishing interrupting device, means electrically connecting oneof the separable contacts of the interrupting device to said onerelatively stationary switch contact, means electrically connecting theother separable contact of the interrupting device to the relativelystationary terminal, a mechanism for actuating the contact structureincluding a rotatable shaft extending externally of the interruptingdevice and having an operating crank secured to the external endthereof, said crank having two spaced engaging shafts at the end thereofone of which is in the line of motion of the end of the switch blade onopening and the other of which is in the line of motion of the end ofthe switch blade on closing, and an auxiliary contact arm independentfrom the switch blade movable at least during a portion of the openingoperation with the switch blade and electrically interconnecting therelatively stationary terminal with the other relatively stationaryswitch contact.

14. A load-break switch including a pair of spaced terminals, a switchcontact on one of said terminals, disconnecting switch blade meansbridging the switch terminals in the closed circuit position of theswitch, means mount- .ing said switch blade means for rotation about itslongitudinal axis to make and release pressure engagement with saidswitch contact, means for moving said switch blade means into and out ofswinging engagement with said switch contact, an arc-extinguishinginterrupting device mounted on the terminal having said switch contactthereon and out of the space between the spaced terminals, saidinterrupting device having a tubular insulating member supported at oneend on the terminal having the switch contact thereon, a mechanismhousing supported entirely by the other end of said tubular insulatingmember, both said tubular insulating member and said mechanism housingbeing stationary relative to the terminal on which the interruptingdevice is mounted, an operating arm outside said mechanism housing andhaving a shaft extending pivotally into the mechanism housing, saidoperating arm being pivotally movable in opposite directions about theaxis of said shaft during opening and closing movement of the switchblade means, a pair of interrupting contacts one of which is movablewithin said tubular insulating member, said interrupting contacts beingelectrically connected respectively to the terminal having the switchcontact thereon and to said mechanism housing, a

mechanism including an over-center spring in said mechanism housing,said mechanism being connected to said shaft and operated by pivotalmovement of said operating arm, said mechanism moving oneof saidinterrupting contacts to engage the other interrupting contact duringmovement in closing direction before said switch blade means engagessaid switch contact, said mechanism stressing said over-center springduring movement of said shaft by opening movement of the switch blademeans before any movement of the movable interrupting contact in openingdirection, said spring then moving over center and initiating separatingmovement of the interrupting contacts with a snap action at a speedindependent of the speed of movement of said shaft by said switch blademeans.

15. A load-break switch including a pair of spaced terminals, a switchcontact on one of said terminals, disconnecting switch blade meansbridging the switch terminals in the closed circuit position of theswitch, means for moving said switch blade means into and out ofswinging engagement with said switch contact, an arc-extinguishinginterrupting device mounted on the terminal having said switch contactthereon and out of the space between the spaced terminals,'saidinterrupting device having a tubular insulating member supported at oneend on the terminal having the switch contact thereon, amechanismhousing supported entirely by the other end of said tubular insulatingmember, both said tubular insulating member and said mechanism housingbeing stationary relative to the terminal on which the interruptingdevice is mounted, an operating arm outside said mechanism housing andhaving a shaft extending pivotally into the mechanism housing, saidoperating arm being engaged and moved by said switch blade means onlyafter the switch blademeans separates from the switch contact duringopening movement and being engaged and moved by said switch blade meansonly prior to engagement of the switch contact by the switch blade meansduring closing movement and said switch blade means being disengagedfrom the operating arm in both the fully open and fully closed positionsof the switch, said operating arm being pivotally movable in oppositedirections about the axis of said shaft during opening and closingmovement of the switch blade means, a pair of interrupting contacts oneof which is movable within said tubular insulating member, a springmechanism in said mechanism housing and connected to said shaft andoperated by pivotal movement of said operating arm, said springmechanism in the housing being connected to said movable interruptingcontact, auxiliary contact means operable by said switch blade means andcompleting an electrical connection with said mechanism housing and themovable interrupting contact independently of said operating arm and thespring mechanism in the housing when the switch is closed, the spring ofsaid mechanism holding the movable interrupting contact in engagementwith the other interrupting contact when said operating arm and saidswitch blade means are in closed position and also during the first partof the movement of the switch blade means and operating arm in openingdirection, said spring mechanism in the housing acting during furtherpivotal movement of the operating arm in opening direction to actuatethe movable interrupting contact to disengage the other interruptingcontact with a snap action at a speed independent of the speed ofmovement of the operating arm and switch blade means, said springholding said interrupting contacts in separated position when theoperating arm and switch blade means are in open position and movingsaid interrupting contacts to engage position with a snap action uponpivotal movement of the operating arm in closing direction duringclosing movement of the switch blade means.

16. A switch comprising, spaced line terminals, a disconnecting switchblade mounted for movement into and out of bridging engagement withrespect to said line terminals, a circuit interrupting device includingseparable interrupter contacts electrically connected between one ofsaid line terminals and a terminal of said device, a bridging contactarm substantially independent of the switch blade and mounted formovement into and out of bridging engagement with respect to the otherof said line terminals and said device terminal, operating meansoperable in a switch opening operation to first move said switch bladeout of bridging relation with said line terminals while said bridgingcontact arm is substantially stationary, and thereafter to separate theinterrupter contacts, and finally to move said. substantiallyindependent contact arm out of bridging engagement with said other lineterminal and said device terminal.

17. A switch comprising, spaced line terminals, a disconnecting switchblade mounted for movement into and out of bridging engagement withrespect to said line terminals, a circuit interrupting device includingseparable interrupter contacts electrically connected between one ofsaid line terminals and a terminal of said device, a bridging contactarm substantially independent of the switch blade and mounted formovement into and out of bridging engagement with respect to the otherof said line terminals and said device terminal, operating meansoperable in a switch closing operation to first move said substantiallyindependent contact arm into bridging engagement with respect to theother line terminal and the device terminal, and thereafter to close theinterrupter contacts while said'bridging contact arm is substantiallystationary, and finally to close the switch blade into bridgingengagement with respect to the line terminals.

18. A switch comprising, spaced line terminals, a disconnecting switchblade mounted for movement into and out of bridging engagement withrespect to said line ter minals, a circuit interrupting device includingseparable interrupter contacts electrically connected between one v 17of said line terminals and a terminal of said device, a bridging contactarm substantially independent of the switch blade and mounted formovement into and out of bridging engagement with respect to the otherof said line terminals and said device terminal, operating means op:erable in a switch opening operation to first move said switch blade outof bridging relation with said line te'r mirials while said bridgingcontact arm is substantially stationary, and thereafter to separate theinterrupter contacts, and finally to move said substantially independentcontact arm out of bridging engagement with said other line terminal andsaid device terminal, said operating means being operable in a-switchclosing operation to first move said substantially independent contactarm into bridging engagement with respect to the other 'line terminaland the device terminal, and thereafter to close the interruptercontacts while said bridging contact arm is substantially stationary,and finally to close the switch blade into bridging engagement withrespect to the line terminals.

19 A load-break switch including a pair of spaced terminals, a switchcontact on one of said terminals, disconnecting switch blade meansbridging the switch terminals in the closed circuit position of theswitch, means mounting said switch blade means for rotation about itslongitudinal axis to make and release pressure engage ment with saidswitch contact, means for moving said switch blade means into and out ofswinging engagement with said switch contact, an arc-extinguishinginterrupting device mounted on the terminal having said switch contactthereon and out of the space between the spaced terminals, saidinterrupting device having a tubular insulating member supported at oneend on the terminal having the switch contact thereon, a mechanismhousing supported entirely by the other end of said tubular insulatingmember, both said tubular insulating member and said mechanism housingbeing stationary relative to the terminal on which the interruptingdevice is mounted, an operating arm outside said mechanism housing andhaving a shaft extending pivotally into the mechanism housing, saidoperating arm being pivotally movable in opposite directions about theaxis of said shaft during opening and closing movement of the switchblade means, said operating arm and shaft being stationary during thefirst part of the opening movement of the switch blade means until afterthe switch blade means has separated from said switch contact, a pair ofinterrupting contacts one of which is movable within said tubularinsulating member, auxiliary contact means operable by said switch blademeans completing an electrical connection with said mechanism housingand the movable interrupting contact during the time after the switchblade means has separated from said switch contact and until after theoperating arm has been movedto cause separation of the interruptingcontacts, said auxiliary contact means being moved by the switch blademeans to break the electrical circuit to the interrupting contactsduring the later part of the opening movement of the switch blade means,said interrupting contacts being electrically connected respectively tothe terminal having the switch contact thereon and to said mechanismhousing, a mechanism including an over-center spring in said mechanismhousing, said mechanism being connected to said shaft and operated bypivotal movement of said operating arm, said mechanism moving one ofsaid interrupting contacts to engage the other interrupting contactduring movement in clos ing direction before said switch blade meansengages said switch contact, said mechanism stressing said over-centerspring during movement of said shaft by opening movement of the switchblade means before any movement of the movable interrupting contact inopening direction, said spring then moving over center and initiatingseparating movement of the interrupting contacts with a snap action at aspeed independent of the speed of movement of said shaft by said switchblade means.

20. A switch comprising, spaced line terminals, a disconnecting switchblade mounted for rotation about its longitudinal axis and for swingingmovement into and out of bridging engagement with respect to said lineterminals, a switch contact on one of said line terminals engageable bysaid switch blade, operating means for ro tating said switch blade aboutits longitudinal axis after it has been moved to engage the switchcontact to cause pressure engagement therewith, a circuit interruptingdevice having a terminal thereon and including separable interruptercontacts electrically connected between one of said line terminals andsaid terminal of the interrupting device, an auxiliary contact memberelectrically connected to the switch blade and to the other of said lineterminals and movable to engage and disengage said interrupting deviceterminal, said operating means in a switch opening operation firstrotating said switch blade about its longitudinal axis to release thepressure engagement with the switch contact and then beginning swingingmovement of the switch blade out of bridging relation with said lineterminals and causing separation of the interrupter contacts, saidauxiliary contact member remaining in engagement with said interruptingdevice terminal during rotation of the switch blade about itslongitudinal axis and until the interrupter contacts have separated,said switch blade then moving the auxiliary contact member to separatefrom the interrupting device terminal and moving to full open position,and said interrupting device including an interrupting chamber in whichone of the interrupter contacts is moved and the ci cuit interruptingarc is extinguished without any external are being drawn.

21. A load-break switch including a pair of spaced stationary switchterminal members, a switch contact on one of said terminal members,disconnecting switch blade means pivoted on the other of said terminalmembers and bridging the terminal members in the closed circuit positionand pivotally movable into and out of swinging engagement with saidswitch contact, an arc-extinguishing interrupting device including aninterrupter chamber housing of insulating material and a mechanismhousing at one end of the interrupter chamber housing, the other end ofthe interrupter chamber housing being mounted on said terminal membercarrying the switch contact, said arc-extinguishing interrupting devicebeing mounted out of the space between the terminal members, contactstructure for said arc-extinguishing interrupting device including apair of separable interrupting contacts enclosed therewithin, one ofsaid interrupting contacts being on a contact rod movable axially of itslength within the interrupter chamber housing of insulating material, amechanism within the interrupting device for actuating said contact rodand including a rotatable shaft having only one end extending externallyof the mechanism housing through one side thereof and said shaftextending in a direction generally at right angles with the length ofsaid contact rod, operating crank means at the external end of saidshaft, said crank means having two spaced portions at which the crank isengaged and operated, both of said spaced portions having a common planeof movement, a single extension on said switch blade means foralternately engaging each of said spaced portions and operat ing saidcrank means in opposite directions, one of said portions on the crankmeans being in the line of motion of said extension on the switch blademeans during its opening movement and the other said portion on thecrank means being in the line of motion of the same said extension onthe switch blade means during its closing movement, and the said twospaced portions on the crank means and the shaft thereof forming atriangular arrangement mounted on the shaft at one side of theinterrupting device, an auxiliary contact surface carried on saidmechanism housing, and an auxiliary contact portion engaging saidauxiliary contact surface prior to the engagement of the extension onthe switch blade means with said crank means during the opening movementof the switch blade means and thereby completing an electrical circuitbetween the spaced stationary switch terminal members through saidinterrupting contacts after said switch blade means has separated fromsaid switch contacts, and said auxiliary contact portion separating fromthe auxiliary contact surface carried on the mechanism housing afterseparation of the interrupting contacts in the interrupting device bymovement of said crank means.

22. A load-break switch including a pair of spaced relatively stationaryswitch contacts, a disconnecting switch blade bridging the switchcontacts in the closed circuit position and adapted to be moved into andout of swinging engagement with one of the relatively stationary switchcontacts, an arc-extinguishing interrupting device having one endthereof disposed adjacent said one relatively stationary switch contactand having the other end thereof extending away from said one relativelystationary switch contact, contact structure for said arc-extinguishinginterrupting device including a pair of separable contacts, a mechanismfor actuating the contact structure, a relatively stationary terminaldisposed adjacent the other end of the arc-extinguishing interruptingdevice, means electrically connecting one of the separable contacts ofthe interrupting device to said one relatively stationary switchcontact, means electrically connecting the other separable contact ofthe interrupting device to the relatively stationary terminal, means forcausing the opening movement of the switch blade to operate saidmechanism, and a movable conducting auxiliary contact arm independentfrom the switch blade electrically interconnecting the relativelystationary terminal with the other relatively stationary switch contact,the switch blade having a hook to pick up the independent auxiliarycontact arm during the opening operation so that the latter will movetherewith to the fully open circuit position.

23. A switch comprising, spaced line terminals, a disconnecting switchblade mounted for movement into and out of bridging engagement withrespect to said line terminals, a circuit interrupting device includingseparable interrupter contacts electrically connected between one ofsaid line terminals and a terminal of said device, a contact armindependent from the switch blade and mounted for movement into and outof bridging engagement with respect to the other of said line terminalsand said device terminal, operating means operable in a switch openingoperation to first move said switch blade out of bridging relation withsaid line terminals, and thereafter to separate the interruptercontacts, and finally to move said independent contact arm out ofbridging engagement with said other line terminal and said deviceterminal, the switch blade having a hook to pick up the independentauxiliary contact arm during the opening operation so that the latterwill move therewith to the fully open circuit position.

24. A switch comprising, spaced line terminals, a disconnecting switchblade mounted for movement into and out of bridging engagement withrespect to said line terminals, a circuit interrupting device includingseparable interrupter contacts electrically connected between one ofsaid line terminals and a terminal of said device, a bridging contactarm substantially independent of the switch blade and mounted formovement into and out of bridging engagement with respect to the otherof said line terminals and said device terminal, operating meansoperable in a switch opening operation to first move said switch bladeout of bridging relation with said line terminals while said bridgingcontact arm is substantially stationary, and thereafter to separate theinterrupter contacts, and finally to move said substantially independentcontact arm out of bridging engagement with said other line terminal andsaid device terminal, and means biasing the switch blade and thesubstantially independent contact arm together.

25. A load-break switch including a pair of spaced line terminals, adisconnecting switch blade mounted for movement into and out of bridgingengagement with respect to said line terminals, a circuit interruptingdevice having one end thereof disposed adjacent one line terminal andhaving the other end thereof extending away from said one line terminal,contact structure associated with the circuit interrupting deviceincluding a pair of separable contacts, a mechanism for actuating thecontact structure, a relatively stationary device terminal disposedadjacent said other end of the circuit interrupting device,

means electrically connecting one of the separable contacts of theinterrupting device to said one line terminal and the other separablecontact to the device terminal, means for causing the opening movementof the switch blade to operate said mechanism, an independent auxiliarycontact arm remaining relatively stationary during the initial movementof the switch blade and subsequently movable at least during a portionof the opening opera tion with the switch blade, said auxiliary contactarm interconnecting the device terminal with the other spaced lineterminal, and means biasing the auxiliary contact arm toward thedisconnecting switch blade.

26. A load-break switch including a pair of spaced line terminals, adisconnecting switch blade mounted for movement into and out of bridgingengagement with respect to said line terminals, a circuit interruptingdevice having one end thereof disposed adjacent one line terminal andhaving the other end thereof extending away from said one line terminal,contact structure associated with the circuit interrupting deviceincluding a pair of separable contacts, a mechanism including a crankarm disposed adjacent said other end of the circuit interrupting devicefor actuating the contact structure, a relatively stationary deviceterminal disposed adjacent said other end of the circuit interruptingdevice, means electrically connecting one of the separable contacts ofthe interrupting device to said one line terminal and the otherseparable contact to the device terminal, means for causing the openingmovement of the switch blade to rotate said crank arm to actuate themechanism, an independent auxiliary contact arm remaining relativelystationary during the initial movement of the switch blade While thelatter rotates the crank arm and subsequently movable at least during aportion of the opening operation with the switch blade, and saidauxiliary contact arm interconnecting the device terminal with the otherspaced line terminal.

References Cited in the file of this patent UNITED STATES PATENTS

